Each of these stone slabs has two arrows on it. To open the manhole, you must fill the board with slabs so that all four rows, all four columns, and both diagonals contain one of each direction of arrow. Some of the slabs are already firmly fixed in place, but you can freely rotate the rest.
Start by placing panels next to the ones already fixed in place.
US Version
The bottom-right corner of the board is a good place to start, as there's only one orientation of panel that can fit there. Check the row and column for this space, and choose a panel that will fill the space without duplicating the existing arrows.
UK Version
The bottom-right corner of the board is a good place to start, as there's only one orientation of panel that can fit there. Check the rows and column for this space and choose a panel that will fill the space without duplicating the existing arrows.
The space on the bottom right of the board needs a piece with a left and right arrow on it. The left arrow should be on top, as there's already a right arrow in the third row down.
Next, let's look at the space at the top of the second column from the right. After the bottom-right panel is in position, it should be easy to work out which one goes here.
With the first two hints, you should have already filled in the right half of the board.
US Version
Now let's see which panel fits in the center of the leftmost column. You'll be completing two rows with this piece, so there's only one panel that could go here.
UK Version
Now let's see which panel fits in the centre of the leftmost column. You'll be completing two rows with this piece, so there's only one panel that could go here.
US Version
You should have gathered from Hint 3 that the panel with a right and a down arrow goes in the center of the leftmost column on the board.
That leaves only two spaces left to fill. Don't forget that you need to pay attention to the diagonals, or else you won't know which panel goes where.
UK Version
You should have gathered from Hint 3 that the panel with a right and a down arrow goes in the centre of the leftmost column on the board.
That leaves only two spaces left to fill. Don't forget that you need to pay attention to the diagonals, or else you won't know which panel goes where.